KR102495161B1 - Pyrimidine derivative and organic electroluminescence element - Google Patents

Abstract

According to the present invention, a pyrimidine derivative represented by the following general formula (1) is provided. The pyrimidine derivatives of the present invention are novel compounds and exhibit (1) good electron injection properties, (2) high electron mobility, (3) excellent hole blocking properties, (4) good stability in the form of thin films, and (5) excellent Characterized by heat resistance.

Description

Pyrimidine derivatives and organic electroluminescent devices {PYRIMIDINE DERIVATIVE AND ORGANIC ELECTROLUMINESCENCE ELEMENT}

The present invention relates to compounds suitable for the production of organic electroluminescent devices and to organic electroluminescent devices (hereafter often referred to as organic EL devices). More specifically, the present invention relates to a pyrimidine derivative and an organic EL device using the pyrimidine derivative.

An organic EL element is a self-luminous element characterized by higher brightness and higher visibility than a liquid crystal element, which makes it possible to realize a clearer display, and is therefore being actively studied.

In 1987, Eastman Kodak Company's C. W. Tang et al. Layered structure elements comprising various materials to share these individual roles have been developed, and organic EL elements using organic materials have been put into practice. The organic EL element is constructed by laminating layers of a phosphor capable of transporting electrons and an organic material capable of transporting holes. Because of this arrangement, the organic EL element is tuned to inject positive and negative charges into a layer of phosphor to perform light emission, thereby obtaining a high luminance of 1,000 cd/m 2 or more at a voltage of 10 V or less.

To date, many improvements have been made in the practical use of organic EL devices. For example, high efficiency and durability generally have a layered structure in which the role given by each layer is further segmented, i.e., an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, electron injection on a substrate It is well known that this can be achieved by an electroluminescent device, having a layer, and a cathode.

In order to further improve the luminous efficiency, attempts using triplet excitons have been made, and research in the direction of using phosphorescent emitting compounds is also progressing. Additionally, devices using heat-activated delayed fluorescence (TADF)-based light emission are also being developed. In 2011, Adachi et al. of Kyushu University. realized an external quantum efficiency of 5.3% by using a device comprising a thermally activated delayed fluorescent material.

The light emitting layer is usually prepared by doping a charge transport compound called a host material with a fluorescent compound, a phosphorescent light emitting compound or a material that emits delayed fluorescence. The selection of organic materials in an organic EL device seriously affects the characteristics of the device, such as efficiency and durability.

In an organic EL device, charges injected from both electrodes are combined together in a light emitting layer to emit light. Therefore, in organic EL devices, what is important is how efficiently the charges of holes and electrons pass through the light emitting layer. It is possible to obtain high luminous efficiency when improving electron injection characteristics, improving their mobility, and thus improving the possibility of recombination of holes and electrons, and further confining excitons formed in the light emitting layer. That is, the electron transport material plays an important role. Therefore, it is desired to provide an electron transport material having high electron injection properties, high electron mobility, high hole blocking properties, and high durability against holes.

Regarding device lifetime, in addition, the heat resistance and amorphous form of the material also play important factors. A material having low heat resistance is subjected to thermal decomposition even at a low temperature due to the heat generated when the element is driven, and is deteriorated. A material with low amorphousness causes its thin film to crystallize even in a short period of time and thus causes the device to deteriorate. Therefore, the material to be used must have high heat resistance and good amorphousness.

Tris(8-hydroxyquinoline) aluminum (Alq), a typical luminescent material, is also commonly used as an electron transport material, but its hole blocking properties are not satisfactory.

The insertion method of the hole blocking layer is one of the measurement methods for preventing holes from partially passing through the light emitting layer in order to improve the possibility of recombination of charges in the light emitting layer. As a hole blocking material used to form a hole blocking layer, so far a triazole derivative (see, for example, Patent Document 1), bathocuproin (BCP), a mixed ligand complex of aluminum [aluminum (III) Bis(2-methyl-8-quinolinato)-4-phenyl phenolate (BAlq) and the like are known.

Additionally, 3-(4-biphenylyl)-4-phenyl-5-(4-t-butylphenyl)-1,2,4-triazole (TAZ) as an electron transport material having excellent hole blocking properties ( See Patent Document 2) is known. TAZ has a large work function of about 6.6 eV and a large hole blocking force. Therefore, TAZ is used as a hole blocking material having electron transport properties, and is laminated on the cathode face of a fluorescent light emitting layer or a phosphorescent light emitting layer prepared by vacuum evaporation or by coating, and contributes to improving the efficiency of organic EL devices. However, because of the serious problem of its low electron transport property, TAZ had to be used in combination with an electron transport material having a higher electron transport property.

BCP, on the other hand, has a large work function of the order of 6.7 eV and a large hole blocking power, but a low glass transition temperature (Tg) of the order of 83°C. Therefore, in the form of a thin film, BCP lacks stability and still cannot be said to function sufficiently as a hole blocking layer.

As described above, the material still lacks stability when it is formed into a film or lacks a function of blocking holes to a sufficient extent. In order to improve the characteristics of organic EL devices, therefore, it is desired to provide organic compounds that are excellent in electron injection/transport performance and hole blocking ability and are characterized by high stability in the form of thin films.

Japanese Patent No. 2734341 International Publication No. WO2003/060956

An object of the present invention is to provide an organic compound that has excellent properties, that is, excellent electron injection/transport performance, hole blocking ability and high stability in the form of a thin film, and which can be used as a material for the manufacture of an organic EL device. is to provide

Another object of the present invention is to provide an organic EL device characterized by high efficiency, low driving voltage and great durability by using the compound.

In order to achieve the above object, the present inventors noted that the pyrimidine ring has an affinity for electrons, the nitrogen atom of the pyrimidine ring can be coordinated on a metal, and the pyrimidine ring has excellent heat resistance. The present inventors further designed and chemically synthesized a compound having a pyrimidine ring structure, prepared various organic EL devices by using the compound on an experimental basis, and sharply evaluated the characteristics of the device. As a result, the present inventors have completed the present invention.

That is, according to the present invention, a pyrimidine derivative represented by the following general formula (1) is provided:

(In the expression,

Ar ¹ and Ar ² are each an aromatic hydrocarbon group or a condensed polycyclic aromatic group;

Ar ³ is a hydrogen atom, an aromatic hydrocarbon group or a condensed polycyclic aromatic group;

A ¹ and A ² are each a divalent aromatic hydrocarbon group or a divalent condensed polycyclic aromatic group;

A ³ is a divalent aromatic hydrocarbon group, a divalent condensed polycyclic aromatic group, or a single bond;

B is an aromatic heterocyclic group).

In the pyrimidine derivatives of the present invention,

1) A pyrimidine derivative represented by the following general formula (1-1)

(In the expression,

Ar ¹ to Ar ³ , A ¹ to A ³ and B are as defined in the general formula (1) above);

2) A pyrimidine derivative represented by the following general formula (1-2);

(In the expression,

Ar ¹ to Ar ³ , A ¹ to A ³ and B are as defined in the general formula (1) above);

3) A ¹ or A ² is a phenylene group;

4) A ¹ and A ² are phenylene groups;

5) A ¹ or A ² is a naphthylene group;

6) B is a pyridyl group, bipyridyl group, terpyridyl group, pyrimidinyl group, pyradidinyl group, triadinyl group, pyrrolyl group, pyrazolyl group, imidazolyl group, furyl group, thie Nyl group, quinolyl group, isoquinolyl group, quinoxalinyl group, quinazolinyl group, naphthyridinyl group, indolyl group, benzoimidazolyl group, benzotriazolyl group, benzofuranyl group, benzothienyl group, benzoxazolyl group, benzothiazolyl group, benzothiadiazolyl group, pyridopyrrolyl group, pyridoimidazolyl group, pyridotriazolyl group, acridinyl group, phenadinyl group, phenanthrolinyl group, those with a phenoxadinyl group, a phenothiadinyl group, a carbazolyl group, a carbolinyl group, a dibenzofuranyl group or a dibenzothienyl group;

7) Ar ² is a phenyl group;

8) Ar ² is a condensed polycyclic aromatic group and, specifically, a naphthyl group or a phenanthrenyl group;

9) Ar ³ is a hydrogen atom;

10) Ar ¹ is a phenyl group having a substituent (the substituent being possessed by a phenyl group which is a condensed polycyclic aromatic group having no substituent); and

11) Ar ¹ is a condensed polycyclic aromatic group and, specifically, a condensed polycyclic aromatic group having no substituent

this is preferable

According to the present invention, there is further provided an organic EL device having a pair of electrodes and at least one organic layer held therein, and at least one organic layer containing a pyrimidine derivative.

In the organic EL device of the present invention, it is preferable that the organic layer containing the pyrimidine derivative is an electron transport layer, a hole blocking layer, a light emitting layer or an electron injection layer.

The pyrimidine derivative of the present invention is a novel compound and has (1) good electron injection properties, (2) high electron mobility, (3) excellent hole blocking ability, (4) good stability in its thin film form, and (5) excellent heat resistance. characterized by Specifically, as demonstrated in the Examples shown below, the pyrimidine derivatives of the present invention exhibit a work function greater than that of 5.5 eV exhibited by conventional hole transport materials by about 1, and therefore exhibit very high hole blocking power. have

As compared to conventional materials, the pyrimidine derivatives of the present invention have favorable electron injection properties and are characterized by high electron mobility. Therefore, when the pyrimidine derivative of the present invention is used as a material for constituting the electron injection layer and/or the electron transport layer of an organic EL device, electrons are highly effectively transported from the electron transport layer into the light emitting layer to improve the luminous efficiency, and at the same time, It contributes to lowering the driving voltage of the organic EL element and improving durability.

The pyrimidine derivatives of the present invention have excellent hole blocking ability as well as superior electron transport properties compared to those of conventional materials, and, moreover, remain very stable in the form of their thin films. By using the pyrimidine derivative of the present invention as a material constituting the hole blocking layer of an organic EL device, therefore, an organic EL device can be driven for a reduced voltage, while maintaining improved resistance against current and high luminous efficiency, while maintaining high luminous efficiency. Indicates maximum brightness.

The pyrimidine derivatives of the present invention have higher electron transport properties and wider band gaps than those of conventional materials, and can be used as materials constituting light emitting layers of organic EL devices. Specifically, when used as a host material of a light emitting layer, the pyrimidine derivative of the present invention may have a fluorescent light emitting material or a phosphorescent light emitting material called a dopant. Therefore, an organic EL element driven for a reduced voltage and characterized by improved luminous efficiency can be realized.

The organic EL device of the present invention has higher electron injection power, greater mobility, greater hole blocking properties, higher stability against holes and higher stability in the form of a thin film than those of conventional electron transport materials. Pyrimidine derivatives are used. Therefore, the organic EL device confines the excitons formed in the light emitting layer, improves the possibility of recombination with holes and electrons, obtains high luminous efficiency and high power efficiency, and as a result, luminance starting voltage and feasible driving voltage reduction, and an extended device lifetime can be realized.

[Figure 1] Diagrams showing compounds 1 to 5, which are pyrimidine derivatives of the present invention.
[Figure 2] Diagrams showing compounds 6 to 10, which are pyrimidine derivatives of the present invention.
[Figure 3] Diagrams showing compounds 11 to 15, which are pyrimidine derivatives of the present invention.
[Figure 4] Diagrams showing compounds 16 to 20, which are pyrimidine derivatives of the present invention.
[Figure 5] Diagrams showing compounds 21 to 26, which are pyrimidine derivatives of the present invention.
[Figure 6] Diagrams showing compounds 27 to 32, which are pyrimidine derivatives of the present invention.
[Figure 7] Diagrams showing compounds 33 to 37, which are pyrimidine derivatives of the present invention.
[Figure 8] Diagrams showing compounds 38 to 42, which are pyrimidine derivatives of the present invention.
[Figure 9] Diagrams showing compounds 43 to 47, which are pyrimidine derivatives of the present invention.
[Figure 10] Diagrams showing compounds 48 to 52, which are pyrimidine derivatives of the present invention.
[Figure 11] A diagram showing compounds 53 to 57, which are pyrimidine derivatives of the present invention.
[Figure 12] Diagrams showing compounds 58 to 62, which are pyrimidine derivatives of the present invention.
[Figure 13] Diagrams showing compounds 63 to 67, which are pyrimidine derivatives of the present invention.
[Figure 14] Diagrams showing compounds 68 to 72, which are pyrimidine derivatives of the present invention.
[Figure 15] Diagrams showing compounds 73 to 76, which are pyrimidine derivatives of the present invention.
[Figure 16] Diagrams showing compounds 77 to 80, which are pyrimidine derivatives of the present invention.
[Figure 17] Diagrams showing compounds 81 to 85, which are pyrimidine derivatives of the present invention.
[Figure 18] Diagram showing compounds 86 to 90, which are pyrimidine derivatives of the present invention.
[Figure 19] Diagrams showing compounds 91 to 95, which are pyrimidine derivatives of the present invention.
[Figure 20] Diagrams showing compounds 96 to 100, which are pyrimidine derivatives of the present invention.
[Figure 21] Diagrams showing compounds 101 to 105, which are pyrimidine derivatives of the present invention.
[Figure 22] Diagrams showing compounds 106 to 110, which are pyrimidine derivatives of the present invention.
[Figure 23] Diagrams showing compounds 111 to 113, which are pyrimidine derivatives of the present invention.
24] ¹ H-NMR chart of the compound of Example 1 (Compound 1).
25] ¹ H-NMR chart of the compound of Example 2 (Compound 2).
[Fig. 26] ¹ H-NMR chart of the compound of Example 3 (Compound 29).
[Fig. 27] A diagram illustrating the configuration of an organic EL element of the present invention.

The pyrimidine derivative of the present invention is a novel compound having a pyrimidine ring structure and is represented by the following general formula (1).

Preferably, the pyrimidine derivative of the present invention has a structure represented by the following general formula (1-1) or general formula (1-2).

In the above general formulas (1), (1-1) and (1-2),

Ar ¹ and Ar ² are each an aromatic hydrocarbon group or a condensed polycyclic aromatic group;

Ar ³ is a hydrogen atom, an aromatic hydrocarbon group or a condensed polycyclic aromatic group;

A ¹ and A ² are each a divalent aromatic hydrocarbon group or a divalent condensed polycyclic aromatic group;

A ³ is a divalent aromatic hydrocarbon group, a divalent condensed polycyclic aromatic group, or a single bond;

B is an aromatic heterocyclic group.

<Ar ¹ to Ar ³ >

As an aromatic hydrocarbon group or condensed polycyclic aromatic group represented by Ar ¹ to Ar ³ , specifically a phenyl group, a biphenylyl group, a terphenylyl group, a tetrakisphenyl group, a styryl group, a naphthyl group, anthracenyl group, acenaphthenyl group, phenanthrenyl group, fluorenyl group, indenyl group, pyrenyl group, perylenyl group, fluoranthenyl group, triphenylenyl group, spirobifluorenyl group, etc. are exemplified. It can be.

The aromatic hydrocarbon group or condensed polycyclic aromatic group represented by Ar ¹ to Ar ³ may be unsubstituted or may have a substituent. As the substituent, the following groups can be exemplified in addition to a deuterium atom, a cyano group and a nitro group.

halogen atoms such as fluorine atoms, chlorine atoms, bromine atoms and iodine atoms;

Alkyl groups having 1 to 6 carbon atoms, such as methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, tert-butyl groups, n-pentyl groups, isopentyl groups, neopentyl group and n-hexyl group;

alkyloxy groups having 1 to 6 carbon atoms, such as methyloxy groups, ethyloxy groups and propyloxy groups;

alkenyl groups such as vinyl groups and allyl groups;

aryloxy groups such as phenyloxy groups and tolyloxy groups;

arylalkyloxy groups such as benzyloxy groups and phenethyloxy groups;

Aromatic hydrocarbon groups or condensed polycyclic aromatic groups such as phenyl groups, biphenylyl groups, terphenylyl groups, naphthyl groups, anthracenyl groups, phenanthrenyl groups, fluorenyl groups, indenyl groups, pyrenyl groups, a perylenyl group, a fluoranthenyl group, a triphenylenyl group, a spirobifluorenyl group and an acenaphthenyl group;

Aromatic heterocyclic groups such as pyridyl groups, furanyl groups, thienyl groups, furyl groups, pyrrolyl groups, quinolyl groups, isoquinolyl groups, benzofuranyl groups, benzothienyl groups, indolyl groups, carboxylic a bazolyl group, a benzoxazolyl group, a benzthiazolyl group, a quinoxalyl group, a benzimidazolyl group, a pyrazolyl group, a dibenzofuranyl group, a dibenzothienyl group and a carbolinyl group;

arylvinyl groups such as styryl groups and naphthylvinyl groups; and

acyl groups such as acetyl groups and benzoyl groups.

Alkyl groups having 1 to 6 carbon atoms, alkenyl groups having 1 to 6 carbon atoms and alkyloxy groups may be straight-chain or may have a branched form. The substituents may be unsubstituted or may be substituted with the substituents described above. The substituents may be independent of each other and may not form any ring, but are further bonded to each other through a single bond, through a substituted or unsubstituted methylene group, or through an oxygen atom or a sulfur atom to form a ring can do.

Preferred examples of Ar ¹ are a phenyl group and a condensed polycyclic aromatic group, more preferably a phenyl group, a biphenylyl group, a naphthyl group, anthracenyl group, an acenaphthenyl group, a phenanthrenyl group, and a fluorenyl group. group, an indenyl group, a pyrenyl group, a perylenyl group, a fluoranthenyl group, a triphenylenyl group and a spirobifluorenyl group, specifically preferably a phenyl group, a biphenylyl group, a naphthyl group group, anthracenyl group, acenaphthenyl group, phenanthrenyl group and spirobifluorenyl group. Here, Ar ¹ may be unsubstituted or may have a substituent. However, in terms of molecular anisotropy as a whole, Ar ¹ having substituents must have 6 to 25 carbon atoms as a whole, more preferably 6 to 20 carbon atoms as a whole. As Ar ¹ having a substituent, it is desired to use a phenyl group. As substituents, it is desired here to use condensed polycyclic aromatic groups and specifically, naphthyl groups, anthracenyl groups, acenaphthenyl groups, phenanthrenyl groups, pyrenyl groups, fluoranthenyl groups or triphenylenyl groups. do. When Ar ¹ is a substituted phenyl group, the substituent may have additional substituents. Preferably, however, the substituents have no further substituents. A preferable example of Ar ¹ having no substituent is a condensed polycyclic aromatic group.

Preferable examples of Ar ² are an unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted condensed polycyclic aromatic group, and a 9,9-dimethylfluorenyl group. Specifically, preferred examples of Ar ² include an unsubstituted phenyl group or a biphenylyl group; substituted or unsubstituted naphthyl groups, anthracenyl groups, acenaphthenyl groups, phenanthrenyl groups, indenyl groups, pyrenyl groups, perylenyl groups, fluoranthenyl groups and triphenylenyl groups; and a 9,9-dimethylfluorenyl group. More preferred examples of Ar ² include an unsubstituted phenyl group or a biphenylyl group; unsubstituted naphthyl groups, anthracenyl groups, phenanthrenyl groups, pyrenyl groups, fluoranthenyl groups and triphenylenyl groups; and a 9,9-dimethylfluorenyl group.

Preferable examples of Ar ³ include a hydrogen atom and a phenyl group having a substituent. A more preferable example of Ar ³ is a hydrogen atom. As the substituent of the "phenyl group having a substituent" which is a preferred form of Ar ³ , aromatic hydrocarbon groups such as a phenyl group, a biphenylyl group, and a terphenyl group; or condensed polycyclic aromatic groups such as naphthyl groups, anthracenyl groups, acenaphthenyl groups, phenanthrenyl groups, fluorenyl groups, indenyl groups, pyrenyl groups, perylenyl groups, fluoranthenyl groups, and A triphenylenyl group can be exemplified. More preferable examples are a phenyl group, a naphthyl group, anthracenyl group, a phenanthrenyl group, a pyrenyl group, a fluoranthenyl group and a triphenylenyl group.

Ar ¹ and Ar ² may be the same group, but are preferably different groups from the viewpoint of stability of the shape of the thin film. Cases in which Ar ¹ and Ar ² are different groups include cases where they are bonded to the pyrimidine ring at different positions, cases where they have different substituents, or cases where they have substituents and substituents bonded to Ar ¹ and Ar ² at different positions. .

Ar ² and Ar ³ may be the same group. However, compounds tend to crystallize because the molecule as a whole acquires good symmetry. Therefore, from the viewpoint of the stability of the thin film, it is desired that Ar ² and Ar ³ are different groups.

<A ¹ to A ^3>

The divalent aromatic hydrocarbon group or divalent condensed polycyclic aromatic group represented by A ¹ to A ³ is formed by removing two hydrogen atoms from an aromatic hydrocarbon or condensed polycyclic aromatic ring. In this case, specific examples of the aromatic hydrocarbon or condensed polycyclic aromatic ring include benzene, biphenyl, terphenyl, tetrakisphenyl, styrene, naphthalene, anthracene, acenaphthalene, fluorene, phenanthrene, indan, pyrene and triphenylene. include

The aromatic hydrocarbon group or condensed polycyclic aromatic group represented by A ¹ to A ³ may be unsubstituted or may have a substituent. As the substituent, the same as those exemplified above as the substituent which may be possessed by the aromatic hydrocarbon group represented by Ar ¹ to Ar ³ or the condensed polycyclic aromatic group can be exemplified. The conformation acquired by the substituent is also the same.

A ¹ or A ² is preferably a divalent group formed by removing two hydrogen atoms from benzene (phenylene group) or a divalent group formed by removing two hydrogen atoms from naphthalene (naphthylene group). More preferably, one of A ¹ or A ² is a phenylene group and the other is a naphthylene group, or A ¹ and A ² have a sublimation temperature that is too high in the case where the organic EL device is formed by the vacuum evaporation method. Both are phenylene groups from such a point of view that they do not rise.

A ³ is preferably a single bond since the sublimation temperature does not become too high when the organic EL element is formed by vacuum evaporation.

<B>

Specific examples of the aromatic heterocyclic group represented by B include triazinyl group, pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, thienyl group, quinolyl group, isoquinolyl group, benzofuranyl group, benzothienyl group, indolyl group, carbazolyl group, benzoxazolyl group, benzothiazolyl group, quinoxalinyl group, benzoimidazolyl group, pyrazolyl group, dibenzofuranyl group, dibenzothie Nyl group, naphthylidinyl group, phenanthrolinyl group, acridinyl group, carbolinyl group, bipyridyl group, terpyridyl group, pyradinyl group, imidazolyl group, quinazolinyl group, benzotria zolyl group, benzothiadiazolyl group, pyridopyrrolyl group, pyridoimidazolyl group, pyridotriazolyl group, phenadinyl group, phenoxadinyl group, phenothiadinyl group and the like.

The aromatic heterocyclic group represented by B may be unsubstituted or may have a substituent. As the substituent, those identical to the above-mentioned substituents that may be possessed by the aromatic hydrocarbon group represented by Ar ¹ to Ar ³ or the condensed polycyclic aromatic group can be exemplified. The same also holds for the form assumed by the substituents.

As group B, a nitrogen-containing heterocyclic group such as a triazinyl group, pyridyl group, pyrimidinyl group, pyrrolyl group, quinolyl group, isoquinolyl group, indolyl group, carbazolyl group, benzoxa A zolyl group, a benzothiazolyl group, a quinoxalinyl group, a benzoimidazolyl group, a pyrazolyl group, a naphthylidinyl group, a phenanthrolinyl group, an acridinyl group and a carbolinyl group are preferred. Triazinyl group, pyridyl group, pyrimidinyl group, quinolyl group, isoquinolyl group, indolyl group, quinoxalinyl group, benzoimidazolyl group, naphthyridinyl group, phenanthrolinyl group or acridinyl group Giga is more preferred. A pyridyl group, a pyrimidinyl group, a quinolyl group, an isoquinolyl group, an indolyl group, a quinoxalinyl group, a benzimidazolyl group, a phenanthrolinyl group or an acridinyl group are most preferred.

Alternatively, as group B, a pyridyl group, a bipyridyl group, a terpyridyl group, a pyrimidinyl group, a pyradidinyl group, a triazinyl group, a pyrrolyl group, a pyrazolyl group, an imidazolyl group, a furyl group, Thienyl group, quinolyl group, isoquinolyl group, quinoxalinyl group, quinazolinyl group, naphthyridinyl group, indolyl group, benzimidazolyl group, benzotriazolyl group, benzofuranyl group, benzothie Nyl group, benzoxazolyl group, benzothiazolyl group, benzothiadiazolyl group, pyridopyrrolyl group, pyridoimidazolyl group, pyridotriazolyl group, acridinyl group, phenadinyl group, phenanthrolinyl group , a phenoxadinyl group, a phenothiadinyl group, a carbazolyl group, a carbolinyl group, a dibenzofuranyl group or a dibenzothienyl group is preferred.

1 to 23 specifically show preferred compounds among the pyrimidine derivatives of the present invention. However, the present invention is not limited only to these compounds. Among the compounds shown in FIGS. 1 to 23 herein, those corresponding to formula (1-1) are compounds 1 to 109 and compounds 111 to 113, and those corresponding to formula (1-2) are compound 110.

<Manufacturing method>

The pyrimidine derivatives of the present invention can be prepared by known methods. For example, pyrimidine derivatives can be prepared as described below. That is, 2,4,6-trichloropyrimidine and an arylboronic acid or arylboronic acid ester having a group corresponding to the group Ar ² are subjected to a Suzuki coupling reaction to form an aryl group corresponding to the group Ar ² at its fourth position. A substituted pyrimidine (hereinafter referred to as a fourth position-substituted pyrimidine) is synthesized. Then, an arylboronic acid or arylboronic acid ester having a heteroaryl group as a substituent having a fourth position-substituted pyrimidine and a group corresponding to the group A ¹ -A ² -A ³ -B is subjected to a Suzuki coupling reaction . Thus, as a substituent, an aryl group having a heteroaryl group corresponding to the group A ¹ -A ² -A ³ -B is introduced into the sixth part of the pyrimidine ring. The pyrimidines thus obtained are called fourth position- and sixth position-substituted pyrimidines. Then, the fourth position- and sixth position-substituted pyrimidines and arylboronic acid or arylboronic acid ester having a group corresponding to Ar ¹ are subjected to a Suzuki coupling reaction, thereby synthesizing the pyrimidine derivative of the present invention do.

Here, when trihalogenated pyrimidines having halogen atoms (eg, chloro groups) substituted at different positions are used, pyrimidine derivatives of the present invention having substituents at different positions can be synthesized.

Further, similarly, an aryl group having an aryl group and/or a heteroaryl group is introduced as a substituent, and a halogen group is introduced into the pyrimidine ring by performing halogenation with N-bromosuccinic acid imide, after which a Suzuki coupling reaction It is acceptable to synthesize pyrimidine derivatives of the present invention having substituents at different positions by introducing an aryl group having an aryl group and/or a heteroaryl group as a substituent and using a monohalogenated pyrimidine or a dihalogenated pyrimidine. do.

The synthesized compound is purified by column chromatography, by an adsorption purification method using silica gel, activated carbon or activated clay, by a recrystallization method or by a crystallization method using a solvent or by a sublimation purification method or the like. Additionally, compounds are identified by NMR analysis.

Work function and glass transition temperature (Tg) can be measured as physical properties. The work function is an index for hole blocking. The work function can be measured by forming a thin film having a thickness of 100 nm on an ITO substrate and using an ionization potential measuring device (Model PYS-202, manufactured by Sumitomo Heavy Industries, Ltd.). Additionally, the glass transition temperature serves as an indicator of the stability of the thin film. The glass transition temperature (Tg) is measured by using a powder and a highly sensitive differential scanning calorimeter (DSC 3100SA, manufactured by Bruker AXS K.K.).

<Organic EL element>

The pyrimidine derivative of the present invention can advantageously be used as a material for an organic layer in an organic EL device. An organic EL device formed using the pyrimidine derivative of the present invention (hereafter sometimes referred to as the organic EL device of the present invention) is an anode, a hole transport layer, a light emitting layer, an electron transport layer and a cathode comprising a substrate such as a glass substrate or a transparent plastic substrate ( For example, a structure formed continuously on a polyethylene terephthalate substrate) is taken.

The organic EL device of the present invention may further have a hole injection layer between the anode and the hole transport layer. Alternatively, the organic EL device may have an electron injection layer between the electron transport layer and the cathode, an electron-blocking layer between the light emitting layer and the hole transport layer, or a hole blocking layer between the light emitting layer and the electron transport layer.

In the organic EL device of the present invention, some organic layers may be omitted. For example, a layer serving both as a hole blocking layer and an electron transporting layer, a layer serving both as a hole injection layer and a hole transporting layer, and a layer serving both as an electron injection layer and an electron transporting layer can be formed.

In the organic EL device of the present invention, further, the organic layer may be a lamination of two or more layers having the same function. Specifically, the hole transport layer may be a lamination of two layers, the light emitting layer may be a lamination of two layers, and the electron transport layer may be a lamination of two layers.

27 shows, for example, a transparent anode 2, a hole injection layer 3, a hole transport layer 4, a light emitting layer 5, a hole blocking layer 6, an electron transport layer 7, an electron injection layer 8, and a cathode 9 formed in this order on a glass substrate 1. The structure of the layer of the organic EL element which has is illustrated. Layers constituting the organic EL element of the present invention will now be described below.

(Anode 2)

As anode 2, an electrode material having a large work function, such as ITO or gold, is used.

(hole injection layer 3)

A hole injection layer 3 is provided between the cathode 2 and the hole transport layer 4 . As the hole injection layer 3, a porphyline compound represented by a known material such as copper phthalocyanine; triphenylamine derivatives of the star burst type; Triphenylamine trimers and triphenylamine tetramers, for example, arylamine compounds having 3 or more triphenylamine structures in a molecule (the triphenylamine structures are linked to each other through a single bond or a divalent group having no heteroatom). connected); receptor-type heterocyclic compounds such as hexacyanoazatriphenylene; and coating-type polymeric materials may be used.

These materials may be used as a single kind to form a film, but may also be used as a mixture of a plurality of materials to form a film. In addition to using materials commonly used for forming the hole injection layer, also trisbromophenylamine hexachloroantimony, radialene derivatives (refer to International Laid-Open WO2014/009310), or the like, or benzidine as a partial structure thereof It is possible to use materials P-doped with polymeric compounds having derivatives, such as TPD.

The hole injection layer 3 can be obtained when a thin film is formed by using the above material depending on a known method such as a vacuum evaporation method, a spin-coating method or an ink-jet method. The layer described below can also be similarly obtained by forming a thin film by a known method such as vacuum evaporation, spin-coating method or ink-jet method.

(hole transport layer 4)

A hole transport layer 4 is provided between the anode 2 and the light emitting layer 5. For the hole transport layer 4, the following materials may be used.

Benzidine derivatives such as

N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (TPD);

N,N'-diphenyl-N,N'-di(α-naphthyl)benzidine (NPD);

N,N,N',N'-tetrabiphenylylbenzidine;

1,1-bis[(di-4-tolylamino)phenyl] cyclohexane (TAPC); and

Various triphenylamine trimers and tetramers.

These materials may be used as a single kind to form a film, but may also be used as a mixture of a plurality of materials to form a film. Additionally, the hole transport layer 4 may have a single-layer structure or a multi-layer structure.

In addition to using materials commonly used for forming the hole transport layer 4, also trisbromophenylaminehexachloroantimony, radialene derivatives (refer to International Laid-Open WO2014/009310), or the like, or having a benzidine derivative as a partial structure thereof. It is possible to use materials P-doped with polymeric compounds, such as TPD.

In the present invention, a coating-type polymeric material such as poly(3,4-ethylenedioxythiophene) (PEDOT)/poly(styrene sulfonate) (PSS) is used to form the hole injection layer 3 and/or the hole transport layer 4. It is permissible to use

(electron-blocking layer)

Although not illustrated in FIG. 27 , an electron-blocking layer may be provided between the hole transport layer 4 and the light emitting layer 5 . For the electron-blocking layer, a known compound having an electron-blocking action can be used. As known compounds, the following compounds can be exemplified.

Carbazole derivatives such as

4,4',4"-tri(N-carbazolyl)triphenylamine (TCTA);

9,9-bis[4-(carbazol-9-yl)phenyl]fluorene;

1,3-bis(carbazol-9-yl)benzene (mCP);

2,2-bis(4-carbazol-9-ylphenyl)adamantane (Ad-Cz);

A compound having a triphenylsilyl group and a triarylamine structure, such as

9-[4-(carbazol-9-yl)phenyl]-9-[4-(triphenylsilyl)phenyl]-9H-fluorene;

monoamine compounds with high electron blocking properties; and

Various triphenylamine dimers.

These materials may be used as a single kind to form a film, but may also be used as a mixture of a plurality of materials to form a film. Additionally, the electron-blocking layer may have a single-layer structure or a multi-layer structure.

(Emitting layer 5)

For the light-emitting layer 5, any other known light-emitting material can be used in addition to the pyrimidine derivative of the present invention. As known light emitting materials, various metal complexes such as metal complexes of quinolinol derivatives such as Alq ₃ ; anthracene derivatives; bisstyrylbenzene derivatives; pyrene derivatives; oxazole derivatives; polyparaphenylenevinylene derivatives; etc. can be exemplified.

It is also possible to constitute the light emitting layer 5 by using a host material and a dopant material. As the host material, thiazole derivatives; benzimidazole derivatives; polydialkylfluorene derivatives; and a heterocyclic compound having an indole ring as a partial structure of the condensed ring other than using the pyrimidine derivative and the above-mentioned light emitting material of the present invention can be used.

As the dopant material, pyrine derivatives; anthracene derivatives; quinacridone, cumalin, rubrene, perylene and their derivatives; benzopyran derivatives; rhodamine derivatives; aminostyryl derivatives; and spirobisfluorene derivatives may be used.

As the luminescent material, it is also possible to use a phosphorescent luminous body. As the phosphorescent emitter, a phosphorescent emitter of a metal complex such as iridium or platinum can be used. Specifically, green phosphorescent emitters such as Ir(ppy) ₃ ; blue phosphorescent emitters such as Flrpic or Flr ₆ ; and red phosphorescent emitters such as Btp ₂ lr(acac).

As the host material, in this case, the following hole injection/transport host material can be used:

carbazole derivatives such as 4,4'-di(N-carbazolyl)biphenyl (CBP), TCTA, mCP;

A heterocyclic compound having an indole ring as part of the condensed ring structure.

Alternatively, the following electron transport host materials may be used:

p-bis(triphenylsilyl)benzene (UGH2);

2,2′,2″-(1,3,5-phenylene)-tris(1-phenyl-1H-benzimidazole) (TPBl).

A high-performance organic EL element can be fabricated by using the host material.

To avoid concentration quenching, the host material is preferably doped with the phosphorescent light emitting material in an amount ranging from 1 to 30% by weight relative to the entire light emitting layer, relying on vacuum coevaporation.

As the light emitting material, it is additionally also possible to use a material that emits delayed fluorescence, such as a CDCB derivative such as PIC-TRZ, CC2TA, PXZ-TRZ or 4CzlPN.

These materials may be used as a single kind to form a film, but may also be used as a mixture of a plurality of materials to form a film. Additionally, the light-emitting layer 5 may have a single-layer structure or a multi-layer structure.

(hole blocking layer 6)

A hole blocking layer 6 may also be formed between the light emitting layer 5 and the electron transporting layer 7 . For the hole blocking layer 6, any other known compound having a hole blocking action can be used as well as the pyrimidine derivative of the present invention. As known compounds having a hole-blocking action, phenanthrolene derivatives such as bassocuproin (BCP), metal complexes of quinolinol derivatives such as BAlq, as well as various rare earth complexes, oxazole derivatives, triazole derivatives, triazole derivatives, Azine derivatives and the like can be exemplified.

These materials can also be used as the material of the electron transport layer 7. These materials may be used singly to form a film, or may be used in a mixture of a plurality of materials to form a film. Additionally, the hole blocking layer 6 may have a single-layer structure or a multi-layer structure.

(electron transport layer 7)

For the electron transport layer 7, not only the pyrimidine derivatives of the present invention but also various metal complexes such as quinolinol derivatives such as Alq ₃ , BAlq; triazole derivatives; triazine derivatives; oxadiazole derivatives; pyridine derivatives; benzimidazole derivatives; thiadiazole derivatives; anthracene derivatives; carbodiimide derivatives; quinoxaline derivatives; pyridoindole derivatives; phenanthroline derivatives; silole derivatives; etc. can be used.

In the case of the electron transporting layer 7, a material N-doped with a metal such as cesium as well as a material normally used for the electron transporting layer can be used.

These materials may be used alone to form a film, or may also be used in a mixture of a plurality of materials to form a film. Additionally, the electron transport layer 7 may have a single-layer structure or a multi-layer structure.

(electron injection layer 8)

An electron injection layer 8 is formed between the electron transport layer 7 and the cathode 9 . For electron injection layer 8, pyrimidine derivatives of the present invention, as well as alkali metal salts such as lithium fluoride and cesium fluoride; alkaline earth metal salts such as magnesium fluoride; metal complexes of quinolinol derivatives such as lithium quinolinol; metal oxides such as aluminum oxide; etc. can be used. However, the electron injection layer 8 can be omitted if the electron transport layer and the cathode are preferably selected.

In the case of the electron injection layer 8, a material N-doped with a metal such as cesium as well as a material normally used for the electron injection layer can be used.

(Cathode 9)

For the cathode 9, an electrode material having a low work function, such as aluminum, or an alloy having a lower work function, such as a magnesium-silver alloy, a magnesium-indium alloy, or an aluminum-magnesium alloy, may be used.

Example

The present invention will now be specifically described by means of examples, but the present invention is not thereby limited in any way, unless departing from the gist and spirit of the present invention.

<Example 1: Compound 1>

Synthesis of 2-(biphenyl-4-yl)-4-phenyl-6-{4'-(pyridin-3-yl)biphenyl-4-yl} pyrimidine;

8.0 g of 2-chloro-4-phenyl-6-{4'-(pyridin-3-yl)biphenyl-4-yl}pyrimidine;

3.8 g of 4-biphenylboronic acid,

tetrakistriphenylphosphine 0.44 g,

7.9 g of potassium carbonate,

80 ml of toluene,

80 ml of tetrahydrofuran, and

40 ml of water

was placed in a reaction vessel purged with nitrogen, heated, and stirred at 80° C. for 12 hours to prepare a reaction solution. The reaction solution was cooled to room temperature, and the organic layer was collected by solution separation. Then, the solution was concentrated under reduced pressure to obtain a crude product, which was then purified by column chromatography (carrier: silica gel, eluent: ethyl acetate/heptane) and then tetrahydrofuran/acetone mixed solvent It was further purified by recrystallization by using 3.0 g of 2-(biphenyl-4-yl)-4-phenyl-6-{4′-(pyridin-3-yl)biphenyl-4-yl}pyrimidine (Compound 1) (yield, 30%) A white powder was obtained.

The obtained white powder was confirmed for its structure by NMR. 24 shows the results of ¹ H-NMR measurement. The following 27 signals of hydrogen were detected by ¹ H-NMR (CDCl ₃ ).

δ(ppm) = 8.94 (1H)

8.83 (2H)

8.64 (1H)

8.43 - 8.32 (4H)

8.07 (1H)

7.97 - 7.35 (18H)

<Example 2: Compound 2>

Synthesis of 2-{4-(naphthalen-1-yl)phenyl}-4-phenyl-6-{4′-(pyridin-3-yl)biphenyl-4-yl}pyrimidine;

The reaction was carried out under the same conditions as in Example 1, but instead of using 4-biphenylboronic acid,

{4-(naphthalen-1-yl)phenyl}boronic acid

It was carried out by using.

As a result, 1.6 g of 2-{4-(naphthalen-1-yl)phenyl}-4-phenyl-6-{4'-(pyridin-3-yl)biphenyl-4-yl}pyrimidine (Compound 2 ) (yield, 15%) of a white powder was obtained.

The obtained white powder was confirmed for its structure by NMR. 25 shows the results of ¹ H-NMR measurement. The following 29 signals of hydrogen were detected by ¹ H-NMR (CDCl ₃ ).

δ(ppm) = 9.00 - 8.81 (3H)

8.65 (1H)

8.51 - 8.28 (4H)

8.11 - 7.32 (21H)

<Example 3: Compound 29>

synthesis of 2,4-bis(phenanthren-9-yl)-6-{4'-(pyridin-3-yl)biphenyl-4-yl}pyrimidine;

The reaction was carried out under the same conditions as in Example 1, but instead of using 2-chloro-4-phenyl-6-{4'-(pyridin-3-yl)biphenyl-4-yl}pyrimidine,

using 2-chloro-4-(phenanthren-9-yl)-6-{4'-(pyridin-3-yl)biphenyl-4-yl}pyrimidine;

Instead of using 4-biphenylboronic acid,

phenanthrene-9-boronic acid

It was carried out by using.

As a result, 1.2 g of 2,4-bis (phenanthren-9-yl) -6- {4'- (pyridin-3-yl) -biphenyl-4-yl} pyrimidine (Compound 29) (yield, 14%) of a white powder was obtained.

The obtained white powder was confirmed for its structure by NMR. 26 shows the results of ¹ H-NMR measurement. The following 31 signals of hydrogen were detected by ¹ H-NMR (CDCl ₃ ).

δ(ppm) = 9.05 - 8.35 (14H)

8.25 - 7.52 (15H)

7.45 - 7.35 (2H)

<Example 4: Compound 96>

synthesis of 4-(naphthalen-1-yl)-2-{4-(naphthalen-1-yl)phenyl}-6-{4′-(pyridin-3-yl)biphenyl-4-yl}pyrimidine;

The reaction was carried out under the same conditions as in Example 1, but instead of using 2-chloro-4-phenyl-6-{4'-(pyridin-3-yl)biphenyl-4-yl}pyrimidine,

using 2-chloro-4-(naphthalen-1-yl)-6-{4'-(pyridin-3-yl)biphenyl-4-yl}pyrimidine;

Instead of using 4-biphenylboronic acid,

4-(naphthalen-1-yl)phenylboronic acid

It was carried out by using.

As a result, 1.9 g of 4-(naphthalen-1-yl)-2-{4-(naphthalen-1-yl)phenyl}-6-{4′-(pyridin-3-yl)biphenyl-4-yl } A white powder of pyrimidine (compound 96) (yield, 28%) was obtained.

The obtained white powder was confirmed for its structure by NMR. The following 31 signals of hydrogen were detected by ¹ H-NMR (CDCl ₃ ).

δ(ppm) = 8.97 (1H)

8.89 (2H)

8.63 (1H)

8.51 - 8.40 (3H)

8.10 - 7.81 (12H)

7.79 - 7.40 (12H)

<Example 5: Compound 98>

synthesis of 4-(naphthalen-1-yl)-2-{4-(naphthalen-2-yl)phenyl}-6-{4′-(pyridin-3-yl)biphenyl-4-yl}pyrimidine;

The reaction was carried out under the same conditions as in Example 1, but instead of using 2-chloro-4-phenyl-6-{4'-(pyridin-3-yl)biphenyl-4-yl}pyrimidine,

using 2-chloro-4-(naphthalen-1-yl)-6-{4'-(pyridin-3-yl)biphenyl-4-yl}pyrimidine;

Instead of using 4-biphenylboronic acid,

4-(naphthalen-2-yl)phenylboronic acid

It was carried out by using.

As a result, 1.8 g of 4-(naphthalen-1-yl)-2-{4-(naphthalen-2-yl)phenyl}-6-{4′-(pyridin-3-yl)biphenyl-4-yl } A white powder of pyrimidine (compound 98) (yield, 26%) was obtained.

The obtained white powder was confirmed for its structure by NMR. The following 31 signals of hydrogen were detected by ¹ H-NMR (CDCl ₃ ).

δ(ppm) = 8.97 (1H)

8.87 (2H)

8.66 (1H)

8.50 - 8.40 (3H)

8.19 (1H)

8.09 - 7.83 (15H)

7.76 (2H)

7.69 (1H)

7.65 - 7.50 (4H)

7.42 (1H)

<Example 6: Compound 100>

synthesis of 4-(naphthalen-2-yl)-2-{4-(naphthalen-9-yl)phenyl}-6-{4′-(pyridin-3-yl)biphenyl-4-yl}pyrimidine;

The reaction was carried out under the same conditions as in Example 1, but instead of using 2-chloro-4-phenyl-6-{4'-(pyridin-3-yl)biphenyl-4-yl}pyrimidine,

using 2-chloro-4-(naphthalen-2-yl)-6-{4'-(pyridin-3-yl)biphenyl-4-yl}pyrimidine;

Instead of using 4-biphenylboronic acid,

4-(phenanthren-9-yl)phenylboronic acid

It was carried out by using.

As a result, 1.5 g of 4-(naphthalen-2-yl)-2-{4-(phenanthren-9-yl)phenyl}-6-{4′-(pyridin-3-yl)biphenyl-4- 1} A white powder of pyrimidine (Compound 100) (yield, 21%) was obtained.

<Example 7: Compound 104>

2-(biphenyl-3-yl)-4-(9,9-dimethylfluoren-2-yl)-6-{4′-(pyridin-3-yl)biphenyl-4-yl}pyrimidine synthesis;

The reaction was carried out under the same conditions as in Example 1, but instead of using 2-chloro-4-phenyl-6-{4'-(pyridin-3-yl)biphenyl-4-yl}pyrimidine,

using 2-chloro-4-(9,9-dimethylfluoren-2-yl)-6-{4'-(pyridin-3-yl)biphenyl-4-yl}pyrimidine;

Instead of using 4-biphenylboronic acid,

3-biphenylboronic acid

It was carried out by using.

As a result, 1.8 g of 2-(biphenyl-3-yl)-4-(9,9-dimethylfluoren-2-yl)-6-{4′-pyridin-3-yl}biphenyl-4- 1} A white powder of pyrimidine (Compound 104) (yield, 23%) was obtained.

The obtained white powder was confirmed for its structure by NMR. The following 35 signals of hydrogen were detected by ¹ H-NMR (CDCl ₃ ).

δ(ppm) = 9.05 (1H)

8.97 (1H)

8.78 (1H)

8.67 (1H)

8.51 - 8.43 (2H)

8.41 - 8.32 (2H)

8.17 (1H)

8.00 - 7.66 (13H)

7.59 - 7.50 (3H)

7.49 - 7.40 (4H)

1.67 (6H)

<Example 8: Compound 107>

synthesis of 4-(biphenyl-4-yl)-2-(phenanthren-9-yl)-6-{4′-(pyridin-3-yl)biphenyl-4-yl}pyrimidine;

The reaction was carried out under the same conditions as in Example 1, but instead of using 2-chloro-4-phenyl-6-{4'-(pyridin-3-yl)biphenyl-4-yl}pyrimidine,

using 2-chloro-4-(biphenyl-4-yl)-6-{4'-(pyridin-3-yl)biphenyl-4-yl}pyrimidine;

Instead of using 4-biphenylboronic acid,

9-phenanthreneboronic acid

It was carried out by using.

As a result, 2.0 g of 4-(biphenyl-4-yl)-2-(phenanthren-9-yl)-6-{4′-pyridin-3-yl}biphenyl-4-yl}pyrimidine ( A yellowish white powder of compound 107) (yield, 30%) was obtained.

The obtained yellowish white powder was confirmed for its structure by NMR. The following 31 signals of hydrogen were detected by ¹ H-NMR (CDCl ₃ ).

δ(ppm) = 8.98 (1H)

8.95 - 8.82 (2H)

8.80 (1H)

8.65 (1H)

8.58 (1H)

8.49 - 8.41 (4H)

8.29 (1H)

8.09 (1H)

7.98 (1H)

7.90 - 7.62 (14H)

7.52 (2H)

7.42 (2H)

<Work function measurement>

By using the compound of the present invention, a film was vapor-deposited on an ITO substrate to a thickness of 100 nm, and by using an ionization potential measuring device (Model PYS-202, manufactured by Sumitomo Heavy Industries, Ltd.) for their work function. measured.

work function

Compound of Example 1 (Compound 1) 6.61 V

Compound of Example 2 (Compound 2) 6.56 V

Compound of Example 3 (Compound 29) 6.49 V

Compound of Example 4 (Compound 96) 6.56 V

Compound of Example 5 (Compound 98) 6.56 V

Compound of Example 6 (Compound 100) 6.56 V

Compound of Example 7 (Compound 104) 6.58 V

Compound of Example 8 (Compound 107) 6.53 V

As described above, the compound of the present invention has a value greater than the work function of 5.5 eV possessed by common hole transport materials such as NPD, TPD and the like, and has a large hole blocking power.

<Measurement of glass transition temperature>

The compounds obtained in the above examples were measured for their glass transition temperatures by using a high-sensitivity differential scanning calorimeter (DSC3100SA, manufactured by Bruker AXS K.K.).

glass transition temperature

Compound of Example 1 (Compound 1) Not determined

Compound of Example 2 (Compound 2) 104°C

Compound of Example 3 (Compound 29) 137°C

Compound of Example 4 (Compound 96) 115°C

Compound of Example 5 (Compound 98) 112°C

Compound of Example 6 (Compound 100) 134°C

Compound of Example 7 (Compound 104) 110°C

Compound of Example 8 (Compound 107) 124°C

The pyrimidine derivative represented by general formula (1) has a glass transition temperature of 100 DEG C or higher, and remains stable in the form of a thin film.

<Device Example 1>

By forming an ITO electrode as the transparent anode 2 on the organic EL element on the glass substrate 1, and on the ITO electrode, a hole injection layer 3, a hole transport layer 4, a light emitting layer 5, and a hole blocking layer 6 also serving as the electron transport layer 7, electron injection Layer 8 and cathode (aluminum electrode) 9 were fabricated by vapor-depositing in this order.

Specifically, glass substrate 1 having an ITO film with a thickness of 150 nm formed thereon was ultrasonically cleaned in isopropyl alcohol for 20 minutes, and then dried on a hot plate heated at 200 DEG C for 10 minutes. Then, the glass substrate with ITO was subjected to UV-ozone treatment for 15 minutes and placed in a vacuum vapor deposition apparatus. The pressure inside was reduced to 0.001 Pa or less.

Thereafter, a hole injection layer 3 was formed. Specifically, a compound HIM-1 of the following structural formula was vapor-deposited to a thickness of 5 nm to cover the transparent anode 2, thereby forming the hole injection layer 3.

Then, a hole transport layer 4 was formed. Specifically, the compound HTM-1 of the following structural formula was vapor-deposited on the hole injection layer 3, thereby forming the hole transport layer 4 to a thickness of 65 nm.

Then, a light emitting layer 5 was formed. Specifically, compound EMD-1 of the following structural formula and compound EMH-1 of the following structural formula are formed on the hole transport layer 4 by binary vapor deposition at a deposition rate of EMD-1:EMH-1 = 5:95 and thereby forming the light emitting layer 5 to a thickness of 20 nm.

Then, a hole blocking layer 6 serving also as the electron transporting layer 7 was formed. Specifically, the compound of Example 1 (Compound 1) and the compound ETM-1 of the following structural formula were deposited on the light emitting layer 5 by binary vapor deposition of the compound of Example 1 (Compound 1):ETM-1 = 50:50 It is formed at a deposition rate, whereby a hole blocking layer 6 also serving as the electron transporting layer 7 is formed with a thickness of 30 nm.

Then, an electron injection layer 8 was formed. Specifically, lithium fluoride was deposited on the hole blocking layer 6 also serving as the electron transporting layer 7 to form an electron injection layer 8 with a thickness of 1 nm.

Finally, aluminum was deposited to a thickness of 100 nm to form a cathode 9.

The fabricated EL element was measured for its luminescent characteristics when it was pressed at a normal temperature in the atmosphere with a direct current voltage. The results were as presented in Table 1.

<Device Example 2>

An organic EL element under the same conditions as in Element Example 1, but instead of using the compound of Example 1 (Compound 1) as a material for forming the hole blocking layer 6 also serving as the electron transporting layer 7, of Example 2 It was prepared using the compound (Compound 2). The fabricated EL element was measured for its luminescent characteristics when it was pressed at a normal temperature in the atmosphere with a direct current voltage. The results were as presented in Table 1.

<Device Example 3>

An organic EL element under the same conditions as in Element Example 1, but instead of using the compound of Example 1 (Compound 1) as a material for forming the hole blocking layer 6 also serving as the electron transport layer 7, It was prepared using the compound (Compound 29). The fabricated EL element was measured for its luminescent characteristics when it was pressed at a normal temperature in the atmosphere with a direct current voltage. The results were as presented in Table 1.

<Device Example 4>

An organic EL element under the same conditions as in Device Example 1, but instead of using the compound of Example 1 (Compound 1) as a material for forming the hole blocking layer 6 also serving as the electron transporting layer 7, of Example 4 It was prepared using the compound (Compound 96). The fabricated EL element was measured for its luminescent characteristics when it was pressed at a normal temperature in the atmosphere with a direct current voltage. The results were as presented in Table 1.

<Device Example 5>

An organic EL element under the same conditions as in Device Example 1, but instead of using the compound of Example 1 (Compound 1) as a material for forming the hole blocking layer 6 also serving as the electron transporting layer 7, It was prepared using the compound (Compound 98). The fabricated EL element was measured for its luminescent characteristics when it was pressed at a normal temperature in the atmosphere with a direct current voltage. The results were as presented in Table 1.

<Device Example 6>

An organic EL element under the same conditions as in Element Example 1, but instead of using the compound of Example 1 (Compound 1) as a material for forming the hole blocking layer 6 also serving as the electron transport layer 7, It was prepared using the compound (Compound 100). The fabricated EL element was measured for its luminescent characteristics when it was pressed at a normal temperature in the atmosphere with a direct current voltage. The results were as presented in Table 1.

<Device Example 7>

An organic EL element under the same conditions as in Element Example 1, but instead of using the compound of Example 1 (Compound 1) as a material for forming the hole blocking layer 6 also serving as the electron transport layer 7, It was prepared using the compound (Compound 104). The fabricated EL element was measured for its luminescent characteristics when it was pressed at a normal temperature in the atmosphere with a direct current voltage. The results were as presented in Table 1.

<Device Example 8>

An organic EL element under the same conditions as in Element Example 1, but instead of using the compound of Example 1 (Compound 1) as a material for forming the hole blocking layer 6 also serving as the electron transporting layer 7, It was prepared using the compound (Compound 107). The fabricated EL element was measured for its luminescent characteristics when it was pressed at a normal temperature in the atmosphere with a direct current voltage. The results were as presented in Table 1.

<Device Comparative Example 1>

An organic EL device under the same conditions as in Device Example 1, but instead of using the compound of Example 1 (Compound 1) as a material for forming the hole blocking layer 6 also serving as the electron transport layer 7, the following structural formula (patent Reference Document 2) was prepared using the compound ETM-2. The fabricated EL element was measured for its luminescent characteristics when it was pressed at a normal temperature in the atmosphere with a direct current voltage. The results were as presented in Table 1.

The EL devices fabricated in Device Examples 1 to 8 and Device Comparative Example 1 were measured for their device lifetimes. The results were as presented in Table 1.

The lifetime of the elements is from when they start to emit light at a luminance of 2000 cd/m2 (initial luminance) by being driven with a constant current, until their luminance decays to 1900 cd/m2 (at 95% when the initial luminance is 100%). Equivalent: 95% attenuation) was measured as the time period until.

[Table 1]

As shown in Table 1, the driving voltage was 3.84 V in Device Comparative Example 1, but was as low as 3.61 to 3.84 V in Device Examples 1 to 8. Additionally, the luminous efficiency was greatly improved from 6.35 cd/A in Device Comparative Example 1 to about 6.53 to 8.43 cd/A in Device Examples 1 to 8. The power efficiency was 5.20 lm/W in Device Comparative Example 1, which was greatly improved, however, to be 5.33 to 7.32 lm/W in Device Examples 1 to 8. Specifically, the life of the device was 55 hours in Comparative Example 1, but greatly extended to 187 to 302 hours in Device Examples 1 to 8.

As described above, compared to a device using compound ETM-2, which is a generally used electron transport material, the organic EL device of the present invention is characterized by excellent luminous efficiency and power efficiency, and furthermore, an elongated device. provides life.

The pyrimidine derivatives of the present invention have good electron injection properties and excellent hole blocking ability, remain stable in the form of thin films, and can be favorably used as compounds for fabricating organic EL devices. When fabricating an organic EL device by using the pyrimidine derivative of the present invention, it is therefore possible to obtain high efficiency, lower the driving voltage, and improve durability. Their use can thus be extended to, for example, household appliances and lighting equipment.

1 glass substrate
2 transparent anodes
3 hole injection layer
4 hole transport layer
5 light emitting layer
6 hole blocking layer
7 electron transport layer
8 electron injection layer
9 cathode

Claims (21)

A compound having a pyrimidine ring structure represented by the following general formula (1-1):

(In the expression,
Ar ¹ is an unsubstituted biphenylyl group or phenanthrenyl group; or a phenylene group having either a naphthyl group or a phenanthrenyl group as a substituent;
Ar ² represents any one of an unsubstituted phenyl group, biphenylyl group, naphthyl group, phenanthrenyl group, and 9,9-dimethylfluorenyl group;
Ar ³ represents a hydrogen atom;
A ¹ and A ² both represent a phenylene group;
A ³ represents a single bond;
B represents a pyridyl group). An organic electroluminescent device having a pair of electrodes and at least one organic layer held therebetween,
An organic electroluminescent device characterized in that the compound having a pyrimidine ring structure according to claim 1 is used as a constituent material of at least one organic layer. The organic electroluminescent device according to claim 2, wherein the organic layer in which the compound having the pyrimidine ring structure is used is an electron transport layer. The organic electroluminescent device according to claim 3, wherein the organic layer in which the compound having the pyrimidine ring structure is used is a hole blocking layer. The organic electroluminescent device according to claim 4, wherein the organic layer in which the compound having the pyrimidine ring structure is used is a light emitting layer. The organic electroluminescent device according to claim 5, wherein the organic layer in which the compound having the pyrimidine ring structure is used is an electron injection layer. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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